1. Field of the Invention
The invention relates to electric hotplates with a hotplate body having a sealed cooking surface, which is generally made from cast iron and is provided on its underside with heating resistors in the form of wire coils received in ribs in an embedding material (cf U.S. Pat. No. 3,300,621).
2. Description of the Prior Art
The cast iron hotplate body of such hotplates is normally surrounded by a pressed on sheet steel trim ring, which has an inverted U or V-shape. They are fitted into the mounting opening of a mounting plate or cooking hob, in that the trim ring is placed on the mounting plate and the hotplate is braced downwards by a clamp (U.S. Pat. Nos. 1,093,754, 2,664,492, British Pat. No. 1 341 753 and DE-OS No. 29 09 776). The connection to a power supply is normally by means of screwed down flexible lines (U.S. Pat. No. 4,348,581). However, hotplates with plug-in connections are also known, which are inserted from above in connector sockets (German Pat. No. 1 021 967).
Wide trim rings are known for use in connection with glass cooking hobs, in order protect the glass plate from the hotplate temperature and for this purpose shielding rings are also provided (U.S. Pat. No. 4,490,603).
Clamps acting in the edge region are frequently used for securing the hotplates (DE-AS No. 1 130 574, U.S. Pat. No. 3,561,020). If in the case of glass mounting plates, the mounting openings are much larger than the diameter of the hotplate body, use has been made of centering means and in part shimmed seals (U.S. Pat. Nos. 3,838,249, 4,491,722 and U.S. patent application No. 245,541, applied for on 19.3.1981, in conjunction with Ser. No. 968,048, filed on 12.12.1978 in the name of Karl Fischer and entitled "Electric cooker plate").
However, it is also conventional practice to use hotplates which do not have a sealed cooking surface and generally comprise spirally wound tubular heaters. These are arranged in optionally interchangeable trays with edges, which rest on a mounting opening of a hob. They are connected by means of plugs fitted to the ends of the tubular heaters and these are laterally inserted into connector sockets.